And while in the mentioned films the problem of integration of people with autism in society is considered, modern medical researchers are not less concerned with the problem of uncovering the biological causes of autism. But this task is far from being an easy one, as can be judged from the fact that there are currently several tens of various theories that pretend if not to discover the single cause of autism, but at least to offer clues as to autism`s most fundamental physiological roots (Novartis Foundation, 2003, pp.8-9). In this regard, let us overview and critically evaluate several theories of autism, each of which highlights different biological mechanisms that are suspected to lead to this developmental disorder.
In general, theories of autism emergence can be divided into large categories. One group of theories, such as for instance opioid excess theories, views autism as a consequence of certain inborn abnormalities. another group, like for example viral infection theories or the approach that accentuates the increased intestinal permeability, links autism with some acquired abnormalities. and there is a group of theories that aims to investigate the possibility of connection between autism and external factors of influence, such as the effects produced by certain types of vaccines. As can be immediately seen, the range of possible causes of autism is quite diverse. To better asses each type of approaches to autism study, we will overview the mentioned opioid excess theories, the viral infection theory, and the theory of the autism origin due to standard vaccinations of children.
The opioid excess theories of autism emphasise abnormalities in the complex workings and influences of opioids and opioid-like substances in the human organism, and particularly in the brain.